Final answer:
Niels Bohr proposed that electrons occupy specific energy levels within the atom, and these levels correspond to specific amounts of energy. Electrons can move between energy levels by gaining or losing precise amounts of energy. This model helps explain why electrons do not emit energy and spiral into the nucleus.
Step-by-step explanation:
Niels Bohr's model of the atom proposed that electrons occupy specific energy levels within the atom. These energy levels are like the rungs of a ladder, with each level corresponding to a specific amount of energy. Electrons can move between energy levels by gaining or losing precise amounts of energy. Bohr's model explained why electrons in an atom do not emit energy and spiral into the nucleus.